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Old 19-10-2012, 09:03 AM
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dvj (John)
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New RH 200 Comes Together

I recently received RH200 from the latest production run. Slowly getting the parts together as seen here. Don't have the focus motor attachment yet, or the proper STL to focuser attachment but managed to do some test shots last evening which showed that the system was clearly out of collimation and will need some adjustment.

First impressions:

Pros:
- Very portable and unique optical design
- Fine focus possible with fingers!
- Excellent finish
- Easy access to collimation and image tilt adjustments

Cons:

- Cost, relative to an FSQ and other refractor solutions
- Lots of glass to keep dew free
- Shower cap dust cover slips off easily
- Special Vixen to D-series adapter needed for mounting
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Old 19-10-2012, 09:19 AM
Poita (Peter)
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High cost realtive to a TAK??
Uh oh... how much are we talking :O
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Old 19-10-2012, 11:01 AM
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ZeroID (Brent)
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And it comes with a Merlot ??
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Old 19-10-2012, 11:24 AM
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Quote:
Originally Posted by Poita View Post
High cost realtive to a TAK??
Uh oh... how much are we talking :O
I can find an excellent condition, used FSQ with accessories for under$3800 US, sometimes even cheaper. Simular field of view.

This RH200 unit new, is closer to $8600 US for the base model.


jg
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Old 19-10-2012, 11:24 AM
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And it comes with a Merlot ??
A Zin actually.
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Old 19-10-2012, 12:57 PM
Poita (Peter)
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*gulp*!

$8600??
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Old 19-10-2012, 01:00 PM
Poita (Peter)
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I guess though that a hyperstar and SCT brand new would set you back nearly $4000 for approx 600mm @f2, and I imagine that this is in a whole other league.

I can't wait to see some images from it, it would be fun to compare.
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Old 19-10-2012, 06:10 PM
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John I urge you to not touch the factory settings for collimation and alignment until you make sure it is NOT your image train!


Bert
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Old 11-12-2012, 12:18 AM
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The latest on the RH 200 project. December 8/9

- OS otor kit for the focuser received and installed.
- Proper STL camera adapter received and installed. Allows rotation of the camera and proper distance to array.
- New OS tube rings for the OTA received. The standard single arm support configuration revealed differential flexure after only 5 min of exposure. I somehow new the standard arrangement was going to be a problem for long exposures unless I used an internal guider.
- Waiting on new D dovetail plates to finish the set up.
- Using SBIG STI autoguider with its short fl video camera lens. Impressed with the STI sensitivity.


Bert is correct. The imaging train is the key issue with these scopes. Initial testing showed the collimation to be spot on, but the array was defintely tilted. Using a 16803 would be nice (and I have one), but honestly thinking a ML 8300 camera and smaller pixels would be a fun project for this unit. My old STL (first generation), is beginning to show its age.

more to come.
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Old 11-12-2012, 02:02 PM
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Quote:
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A Zin actually.
original?
pat
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Old 14-12-2012, 07:12 AM
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Quote:
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original?
pat

Ha Ha. I finally figured out the joke.
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Old 14-12-2012, 07:13 AM
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Ready to Rock!

Finally got everything together and on the mount. Now the fun begins.
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Old 14-12-2012, 07:51 AM
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It looks very good to me John. Those tube rings look far solider than the single leg.

I did consider them for my RH200 but with 18+lbs or 8+kg of image train i was worried about distorting the main optical tube and still have image train flexure!

I really appreciated your comment about the towel on my RH200. It will be replaced by some aluminised space age insulation blanket when I can get some.

The towel is covering six dew straps that keep the whole optic train at a constant temperature plus or minus 0.1C. of a set temperature. I am using a pulse width modulated Peltier controller that is a PID (Proportional Integral Differential). This means that focus is barely affected by ambient temperature change. In Melbourne on a clear night temperature can drop by more than 20C over the night.

You system looks very sexy naked but it would work better insulated and temperature controlled. The other advantage is I leave the heating on 24/7 so dew can never form on any of the optics.

Looking foward to what you can do with your new system. You will find the RH200 is about 2.7 times faster than an FSQ. That is a 15.55 minute exposure with the RH200 is equivalent to 42 minutes on the FSQ.

Bert

Last edited by avandonk; 14-12-2012 at 08:32 AM.
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Old 15-12-2012, 02:27 AM
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Testing last night.

Differential flexure problem has been resolved with the new rings.
As for the stars...... lots of array squaring to do in the nights ahead. It's too bad that a scope of this nature does not have micrometer adjustments on the tip tilt. But I am using a dial guage on the back plate to measure the plate changes at least put some numbers on the the fine adjustments.

I don't have a humdity problem here in the US, but when this scope gets moved to Coonabarabran, the humidity is always high there. I keep the dew heaters always running on the FSQ.

My quick RBG tests are interesting. 300 seconds per sub is about all I'll need. Both my Paramount and AP 1200 can easily run 300 seconds uncorrected so this should be a fun point and shoot system which was really my goal running remotely with this instrument.

more to come, and maybe even an image
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Old 04-01-2013, 04:25 AM
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Collimation of this fast instrument is slowly coming together. Here is the latest CCD inspector result. The stars look excellent in all corners so it helped to precisely measure the tilt changes with a depth guage. Finally, I used FWHM readings in each corner of the STL 11000 image to determine in or out changes on the tilt plate. And the adjustments are very subtle.

http://img846.imageshack.us/img846/1...ectorrh200.jpg

I think I am ready for some real serious imaging but I am still tracking down a differential flexure problem at 20 minute exposures. 5, 10 minutes are perfect.
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